fix typos and incorrect settings (#482)

Author: chenziliang

docs/append-stream-codecs.md

@@ -70,12 +70,11 @@ These codecs are designed to make compression more effective by exploiting speci
 `DoubleDelta` and `Gorilla` codecs are used in Gorilla TSDB as the components of its compressing algorithm. Gorilla approach is effective in scenarios when there is a sequence of slowly changing values with their timestamps. Timestamps are effectively compressed by the `DoubleDelta` codec, and values are effectively compressed by the `Gorilla` codec. For example, to get an effectively stored table, you can create it in the following configuration:
 
 ```sql
-CREATE TABLE codec_example
+CREATE STREAM codec_example
 (
     timestamp DateTime CODEC(DoubleDelta),
     slow_values Float32 CODEC(Gorilla)
 )
-ENGINE = MergeTree()
 ```
 
 ## Encryption Codecs {#encryption-codecs}

docs/append-stream-ttl.md

@@ -66,7 +66,7 @@ TTL d + INTERVAL 1 MONTH DELETE WHERE to_day_of_week(d) = 1;
 
 Creating a stream, where expired rows are recompressed:
 ```sql
-CREATE TABLE stream_for_recompression
+CREATE STREAM stream_for_recompression
 (
     d datetime,
     key uint64,

docs/append-stream.md

@@ -361,8 +361,7 @@ SETTINGS
   shared_disk='s3_disk',
   ingest_batch_timeout_ms=200,
   fetch_threads=2,
-  logstore_codec='zstd',
-  ttl_seconds=86400;
+  logstore_codec='zstd';
 ```
 
 ```sql